Robust Image Hashing Based on Cool and Warm Hue and Space Angle

Table 3

Attack setting in discrimination experiment.

Operation	Parameter	Parameter values
JPEG compression	Quality factor	40, 80
Brightness adjustment	Level	−20, 20
Contrast adjustment	Level	−20, 20
Salt & pepper	Noise level	0.002, 0.006
Image resizing	Ratio	0.8, 1.6
3 × 3 Gaussian filter	Standard deviation	0.2, 0.6
Rotation	Angle	1, 2
Watermark embedding	Transparency	0.3, 0.8
Gamma correction	Gamma	0.75, 1.25
speckle	Noise variance	0.002, 0.006